Rotor structure for motor and motor

Abstract

The utility model relates to the technical field of motors, in particular to a rotor structure for a motor, which comprises a rotor (1), and an air slot structure is arranged on the outer wall of the rotor (1). The air groove structure comprises an air groove (5); the air slots (5) are arranged along the edge of the rotor (1); the surface of the rotor is provided with a plurality of air grooves, and the air grooves can effectively reduce the total area of the surface induction eddy current of the rotor, and can effectively reduce the loss caused by the surface induction eddy current of the rotor. The rotor teeth are arranged between every two adjacent air grooves, and the rotor teeth form airflow during high-speed rotation, so that heat dissipation of the rotor can be facilitated, and the temperature of the rotor can be reduced; the device can effectively ensure the mechanical strength of the motor during high-speed operation while ensuring the electromagnetic performance of the permanent magnet synchronous motor, can suppress rotor eddy current caused by adopting a solid rotor, and can provide certain heat dissipation capability for the rotor.

Description

Technical Field

[0001] The utility model relates to the technical field of motors, and in particular to a rotor structure for a motor and a motor. Background Art

[0002] High-speed permanent magnet synchronous motors use permanent magnet excitation, which has higher torque density and smaller volume, and its control is relatively simple, so it is widely favored by the industry. Usually, the rotor of a permanent magnet synchronous motor is made of laminated silicon steel sheets. However, the rotor made of laminated silicon steel sheets is not conducive to the permanent magnet synchronous motor to adjust higher speeds and power levels. The air gap magnetic field of the permanent magnet synchronous motor has a relatively rich harmonic content. The harmonic air gap magnetic field can cause more significant eddy current losses on the surface of the solid rotor, reducing the overall efficiency of the motor. In addition, the loss accumulation caused by the induced eddy current on the rotor surface can easily lead to local overheating of the rotor surface, further causing the rotor to expand due to heat and cause the motor to fail. The motor dq axis is a coordinate system that describes the magnetic field characteristics of the motor, in which the d axis is perpendicular to the motor magnetic field and the q axis is in the same direction as the magnetic field. The d axis is usually called the direct axis, and the q axis is usually called the quadrature axis.

[0003] After searching, the applicant found that the Chinese patent document with publication number CN207074900U disclosed a built-in permanent magnet motor rotor punching structure for an ISG motor on March 6, 2018, including a circular main body, a plurality of arc-shaped pole spacing magnetic grooves are recessed inward on the outer circumferential wall of the main body, the pole spacing magnetic grooves are evenly arranged on the outer circumferential wall of the main body, the spacing between each two adjacent pole spacing magnetic grooves is equal, and a permanent magnet slot for assembling permanent magnets is provided between each two adjacent pole spacing magnetic grooves on the main body, and each permanent magnet slot has an inner wall recessed inward near the two ends to provide leakage-proof magnetic grooves.

[0004] This device cannot reduce the eddy current loss of the solid rotor of the high-speed permanent magnet synchronous motor. Utility Model Content

[0005] The utility model aims to provide a motor rotor structure and a motor which can reduce the eddy current loss of a solid rotor of a high-speed permanent magnet synchronous motor.

[0006] In order to solve the above technical problems, the technical solution adopted by the utility model is: a rotor structure for a motor, comprising a rotor, an air groove structure is provided on the outer wall of the rotor;

[0007] The air slot structure comprises an air slot; the air slot is arranged along the edge of the rotor.

[0008] Rotor teeth are arranged on the edge of the rotor, and the air grooves are arranged between adjacent rotor teeth.

[0009] The rotor teeth and the air slots are evenly arranged on the outer wall of the rotor.

[0010] The rotor is provided with a permanent magnet slot, and a permanent magnet is arranged in the permanent magnet slot.

[0011] The permanent magnet slot is a V-shaped slot, and its opening faces a side of the rotor close to the rotor teeth.

[0012] The rotor is a magnetic and electrically conductive structural steel block.

[0013] The number of the air slots is equal to the number of the stator slots of the permanent magnet motor.

[0014] The width of the air slot is equal to the tooth width of the rotor tooth; the width of the air slot is 0.5×πD r2 / Q r , where D r2 is the outer diameter of the rotor, Q r is the number of air slots.

[0015] The thickness of the air slot along the radial direction of the rotor is Where μ0 is the vacuum magnetic permeability, μ r is the relative magnetic permeability of the rotor surface, σ is the rotor conductivity; f is the induced eddy current frequency caused by the air gap magnetic field harmonics on the rotor surface; μ r The value range is 1-10.

[0016] A motor comprises the rotor structure for the motor.

[0017] The beneficial effects of this application are:

[0018] The rotor structure of the motor adopts structural steel with both magnetic and electrical properties to replace the traditional lamination process to manufacture the rotor, which can ensure the mechanical strength of the rotor while ensuring the effective torque output of the motor, facilitate the motor to run at a higher speed and power level, and improve the stability and life of the motor.

[0019] The rotor is provided with a plurality of groups of V-shaped permanent magnet slots, and rectangular permanent magnets are embedded in the permanent magnet slots to form a built-in permanent magnet synchronous motor structure, which is convenient for utilizing the magnetic resistance torque formed by the difference in inductance of the motor dq axes to improve the torque output capacity of the high-speed permanent magnet synchronous motor.

[0020] A plurality of air grooves are provided on the surface of the rotor, and the air grooves can effectively reduce the total area of ​​the induced eddy currents on the surface of the rotor, and can effectively reduce the losses caused by the induced eddy currents on the surface of the rotor; and rotor teeth are provided between two adjacent air grooves, and the rotor teeth form airflow when rotating at high speed, which can help the rotor to dissipate heat and reduce the temperature of the rotor.

[0021] When the rotor is installed on the motor, the front and rear ends are suspended in the direction of the motor shaft and are in an open circuit state to the outside, which causes the induced eddy current to close automatically inside the rotor, resulting in an increase in the equivalent internal resistance of the rotor, thereby reducing the size of the eddy current and reducing the eddy current loss of the rotor. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] The specific implementation of the utility model is further described in detail below in conjunction with the accompanying drawings, wherein:

[0023] Figure 1 This is a schematic diagram of the rotor structure of this motor.

[0024] Figure 2 This is the rotor eddy current loss waveform of the finite element simulation of the rotor structure of this motor and the traditional solid rotor structure.

[0025] The marks in the above figure are:

[0026] Markings in the figure are: 1, rotor, 2, shaft hole, 3, permanent magnet slot, 4, permanent magnet, 5, air slot, 6, rotor teeth. DETAILED DESCRIPTION

[0027] The following is a further detailed explanation of the specific implementation methods of the utility model through the description of the embodiments with reference to the accompanying drawings, with the aim of helping those skilled in the art to have a more complete, accurate and in-depth understanding of the inventive concept and technical solution of the utility model and facilitating its implementation.

[0028] Figure 1 The motor rotor structure shown comprises a rotor 1, on which permanent magnet slots 3 are provided, in which permanent magnets 4 are provided; an air slot structure is provided on the outer wall of the rotor 1; and on the rotor 1, an axial hole 2 is provided, in which the motor shaft is placed.

[0029] The rotor 1 is provided with a permanent magnet slot 3, and a permanent magnet 4 is provided in the permanent magnet slot 3, forming a built-in permanent magnet synchronous motor structure, which can improve the torque output capacity of the high-speed permanent magnet synchronous motor. A number of air slots 5 are provided on the surface of the rotor 1, and the air slots 5 can effectively reduce the total area of ​​the surface induced eddy currents of the rotor 1, and can effectively reduce the losses caused by the surface induced eddy currents of the rotor 1. When the rotor 1 is installed on the motor, the front and rear ends along the direction of the motor shaft are suspended in the air, and are in an open circuit state to the outside, resulting in the need for the induced eddy currents to close themselves inside the rotor 1, causing the equivalent internal resistance of the rotor 1 to increase, thereby reducing the size of the eddy currents and reducing the eddy current losses of the rotor 1.

[0030] The air slot structure includes an air slot 5; the air slot 5 is arranged along the edge of the rotor 1. The rotor 1 is a disc structure; a plurality of air slots 5 are evenly arranged along the edge of the rotor 1; the air slot 5 can effectively reduce the total area of ​​the surface induced eddy current of the rotor 1, and can effectively reduce the loss caused by the surface induced eddy current of the rotor 1.

[0031] The edge of the rotor 1 is provided with rotor teeth 6, and air slots 5 are provided between adjacent rotor teeth 6. After the air slots 5 are provided on the edge of the rotor 1, rotor teeth 6 are formed between two adjacent air slots 5. When the rotor teeth 6 rotate at high speed, airflow is formed, which can help dissipate heat from the rotor 1 and reduce the temperature of the rotor 1; it can effectively prevent the surface of the rotor 1 from being overheated locally, and prevent the rotor 1 from expanding due to heat, which may cause the motor to malfunction.

[0032] The rotor teeth 6 and the air slots 5 are evenly arranged on the outer wall of the rotor 1. The rotor teeth 6 and the air slots 5 are evenly arranged along the outer edge of the rotor 1, which can fully reduce the total area of ​​the surface induced eddy currents of the rotor 1, thereby reducing the loss caused by the surface induced eddy currents of the rotor 1.

[0033] The permanent magnet slot 3 is a V-shaped slot, and the opening faces the side of the rotor 1 close to the rotor teeth 6. Two rectangular permanent magnets 4 of the same size are embedded in the permanent magnet slot 3; the permanent magnet slot 3 includes two sides of the V shape, that is, two slots, and the permanent magnets 4 in each slot are of the same polarity; the polarities of different groups of permanent magnets 4 are changed alternately according to the number of motor poles. The number of groups of permanent magnet slots 3 is equal to the number of poles of the motor; in this embodiment, the permanent magnet synchronous motor has a speed of 15000rpm, a pole pair number of 4, that is, a pole number of 8; the number of groups of permanent magnet slots 3 is equal to the number of poles of the motor, which is 8. Permanent magnets 4 are arranged in the permanent magnet slots 3 to form a built-in permanent magnet synchronous motor structure, which can improve the torque output capacity of the high-speed permanent magnet synchronous motor.

[0034] The rotor 1 is a magnetic conductive structural steel block. The rotor 1 uses structural steel with both magnetic and conductive properties instead of traditional lamination processing to manufacture the rotor, which can ensure the mechanical strength of the rotor 1 while ensuring the effective torque output of the motor, facilitate the motor to run at a higher speed and power level, and improve the stability and life of the motor. In this embodiment, the rotor 1 is Q345 low alloy steel with both magnetic and conductive properties, and its resistivity ρ is 25×10 -8 Ω·m, and the yield strength is 345MPa. The resistivity ρ of rotor 1 needs to be multiplied by the end effect coefficient K e Correction is made to take into account the increase in equivalent resistance caused by the eddy current induced by rotor 1 closing inside rotor 1, K e The value range is 1.8-2.0. In this embodiment, K e is 2.0.

[0035] The number of the air slots 5 is equal to the number of the stator slots of the permanent magnet motor. In this embodiment, the number of the air slots 5 on the rotor 1 is equal to the number of the stator slots of the permanent magnet motor, both being 48.

[0036] The slot width of the air slot 5 is equal to the tooth width of the rotor tooth 6; the slot width of the air slot 5 is 0.5×πD r2 / Q r , where D r2 is the outer diameter of rotor 1, Q r is the number of air slots 5. In this embodiment, the slot width of the air slot 5 and the tooth width of the rotor tooth 6 are equal to 0.5×πD. r2 / Q r =0.5×π×168 / 48=5.50mm, where D r2 168mm, Q r It is 48; it can effectively reduce the total area of ​​eddy currents induced by harmonics on the surface of the rotor 1, and reduce the eddy current loss of the rotor 1.

[0037] The thickness of the air slot 5 along the radial direction of the rotor 1 is Where μ0 is the vacuum magnetic permeability, μ r is the relative magnetic permeability of the rotor 1 surface, σ is the electrical conductivity of the rotor 1; f is the frequency of the induced eddy current caused by the air gap magnetic field harmonics on the rotor 1 surface; μ r The value range is 1-10.

[0038] In this embodiment, μ0 is the vacuum magnetic permeability of 4π×10 -7 H / m; μ r is the relative magnetic permeability of the rotor 1 surface of 5; σ is the electrical conductivity of the rotor 1 of 4×10 6 S / m, after correction by end effect coefficient, is 2×10 6 S / m; f is the frequency of the induced eddy current caused by the air gap magnetic field harmonics on the surface of the rotor 1, which can be obtained by |f s (1-v)| is estimated, where f s The stator current frequency is 1000 Hz, v is the -5th order stator phase band harmonic, so the induced eddy current frequency f is 6000 Hz, and the radial thickness of the air slot 5 is calculated to be 2 mm.

[0039] A motor comprises the rotor structure for the motor.

[0040] Figure 2 The rotor eddy current loss waveform diagram of the rotor structure for this motor and the traditional solid rotor structure is simulated by finite element method. Two solid rotor structure topologies are designed in the figure, namely, the structure with air slots 5 and the structure without air slots 5 on the surface of the rotor 1, and other dimensions remain unchanged. Figure 2The motor speed is 15000rpm, and the load torque is 130Nm. The average eddy current loss on the surface of the rotor 1 of the traditional solid rotor structure is 22.36kW, and the average eddy current loss on the surface of the rotor 1 of the solid rotor structure is 11.16kW, which is about 50% lower than the former.

[0041] The specific working process of the utility model is as follows:

[0042] The rotor 1 is made of 0345 low alloy steel; a V-shaped permanent magnet slot 3 is formed on the surface of the rotor 1, and a square permanent magnet 4 is embedded in the permanent magnet slot 3; an air slot 5 is formed on the outer wall of the rotor 1; and the rotor 1 is mounted on the motor shaft.

[0043] The above is an exemplary description of the utility model in conjunction with the accompanying drawings. Obviously, the specific implementation of the utility model is not limited to the above-mentioned method. As long as various non-substantial improvements are made using the method concept and technical solution of the utility model; or the above concept and technical solution of the utility model are directly applied to other occasions without improvement, they are all within the protection scope of the utility model.

Claims

1. A rotor structure for a motor, characterized in that: It comprises a rotor (1), wherein an air groove structure is provided on the outer wall of the rotor (1); The air slot structure comprises an air slot (5); the air slot (5) is arranged along the edge of the rotor (1).

2. A rotor structure for a motor according to claim 1, characterized in that: Rotor teeth (6) are provided on the edge of the rotor (1), and the air slots (5) are provided between adjacent rotor teeth (6).

3. A rotor structure for a motor according to claim 2, characterized in that: The rotor teeth (6) and the air grooves (5) are evenly arranged on the outer wall of the rotor (1).

4. A rotor structure for a motor according to claim 3, characterized in that: The rotor (1) is provided with a permanent magnet slot (3), and a permanent magnet (4) is provided in the permanent magnet slot (3).

5. A rotor structure for a motor according to claim 4, characterized in that: The permanent magnet slot (3) is a V-shaped slot, and its opening faces the side of the rotor (1) close to the rotor teeth (6).

6. A rotor structure for a motor according to claim 5, characterized in that: The rotor (1) is a magnetically conductive and electrically conductive structural steel block.

7. A rotor structure for a motor according to any one of claims 2 to 6, characterized in that: The number of the air slots (5) is equal to the number of the stator slots of the permanent magnet motor.

8. A rotor structure for a motor according to claim 7, characterized in that: The slot width of the air slot (5) is equal to the tooth width of the rotor tooth (6); the slot width of the air slot (5) is 0.5×πD r2 / Q r , where D r2 is the outer diameter of the rotor (1), Q r is the number of air slots (5).

9. A rotor structure for a motor according to claim 8, characterized in that: The thickness of the air groove (5) along the radial direction of the rotor (1) is Where μ0 is the vacuum magnetic permeability, μ r is the relative magnetic permeability of the rotor (1) surface, σ is the electrical conductivity of the rotor (1); f is the frequency of the induced eddy current caused by the air gap magnetic field harmonics on the rotor (1) surface; μ r The value range is 1-10.

10. A motor, characterized in that: The invention comprises a rotor structure for a motor as described in any one of claims 1 to 9.

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